From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_2 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6B7AEC352BE for ; Fri, 17 Apr 2020 15:41:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 547D42223C for ; Fri, 17 Apr 2020 15:41:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729274AbgDQPlp convert rfc822-to-8bit (ORCPT ); Fri, 17 Apr 2020 11:41:45 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46588 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1729110AbgDQPlp (ORCPT ); Fri, 17 Apr 2020 11:41:45 -0400 Received: from bhuna.collabora.co.uk (bhuna.collabora.co.uk [IPv6:2a00:1098:0:82:1000:25:2eeb:e3e3]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 25B52C061A0C; Fri, 17 Apr 2020 08:41:45 -0700 (PDT) Received: from localhost (unknown [IPv6:2a01:e0a:2c:6930:5cf4:84a1:2763:fe0d]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) (Authenticated sender: bbrezillon) by bhuna.collabora.co.uk (Postfix) with ESMTPSA id 0920E2A0613; Fri, 17 Apr 2020 16:41:43 +0100 (BST) Date: Fri, 17 Apr 2020 17:41:40 +0200 From: Boris Brezillon To: Marek Vasut Cc: Christophe Kerello , miquel.raynal@bootlin.com, richard@nod.at, vigneshr@ti.com, lee.jones@linaro.org, robh+dt@kernel.org, mark.rutland@arm.com, tony@atomide.com, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mtd@lists.infradead.org, linux-stm32@st-md-mailman.stormreply.com Subject: Re: [PATCH v2 03/12] bus: stm32-fmc2-ebi: add STM32 FMC2 EBI controller driver Message-ID: <20200417174140.00456f36@collabora.com> In-Reply-To: References: <1586966256-29548-1-git-send-email-christophe.kerello@st.com> <1586966256-29548-4-git-send-email-christophe.kerello@st.com> <20200416215328.53982fef@collabora.com> Organization: Collabora X-Mailer: Claws Mail 3.17.5 (GTK+ 2.24.32; x86_64-redhat-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 17 Apr 2020 17:31:49 +0200 Marek Vasut wrote: > On 4/17/20 5:29 PM, Christophe Kerello wrote: > > > > > > On 4/16/20 9:53 PM, Boris Brezillon wrote: > >> On Wed, 15 Apr 2020 17:57:27 +0200 > >> Christophe Kerello wrote: > >> > >>> The driver adds the support for the STMicroelectronics FMC2 EBI > >>> controller > >>> found on STM32MP SOCs. > >>> > >>> Signed-off-by: Christophe Kerello > >>> Tested-by: Marek Vasut > >>> --- > >>> Changes in v2: > >>>   - call 2 APIs to manage FMC2 enable/disable instead of ops > >>>   - call 2 APIs to manage FMC2 NWAIT shared signal instead of ops > >>> > >>>   drivers/bus/Kconfig          |   11 + > >>>   drivers/bus/Makefile         |    1 + > >>>   drivers/bus/stm32-fmc2-ebi.c | 1091 > >>> ++++++++++++++++++++++++++++++++++++++++++ > >> > >> Hm, I see that other memory bus controller drivers are placed under > >> drivers/memory/, any reason for choosing drivers/bus/? If that's where > >> we want to have all generic memory bus controllers to live it might be > >> worth moving existing drivers to the drivers/bus/ directory at some > >> point. > >> > > > > Hi Boris, > > > > I see this controller as an external bus interface as we are able to > > attach different devices on it, like a PSRAM, an ethernet controller, a > > FPGA, a LCD display, ... > > > > When I had a look at bus/Kconfig file, I have found similar drivers > > (like IMX_WEIM or QCOM_EBI2 drivers). These drivers are able to connect > > devices like NAND Flash, SRAM, ethernet adapters, FPGAs and LCD displays > > as it is written in the Kconfig file. > > > > But, after checking memory/Kconfig file, it is also possible to find > > similar drivers (like ATMEL_EBI driver that is inspired by the WEIM bus > > driver). > > > > So, I will follow the recommendation and I will move it to > > drivers/memory folder if it is the place where this driver should be. > > The EBI isn't a memory bus, you can very well have a non-memory device, > like an external parallel bus memory controller on it. So why should it > be in drivers/memory ? Just like most of those so-called memory bus controllers we have under drivers/memory/ => they are most of the time used to interact with memories but can also be used for other things (Christophe listed a few uses cases). And I'm not pushing one way or the other, all I said was that we should makes things consistent instead of having half of those controller drivers in drivers/memory/ and the other half in drivers/bus/.